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Post by psychedelicode on Jul 15, 2012 7:12:19 GMT -5
Hi, all! I have an '08 jonway 50cc. It ran great and could hold a gps verified 47mph on the flats and i have been clocked at 63 (no ticket) going downhill. That is until I pulled the bodywork off in anticipation for a naked strech. Now its running like crap. It feels almost exactly like I pulled off the 4 hole intake restrictor. Like its getting too much air around 30 and is not able to hit 40. Is it possible that without the bodywork the intake is getting a RAM AIR effect that is throwing the jetting off? I tried adjusting the mixture screw but that has not helped much. The scoot is bone stock with 2400+ miles. i commute 100-130miles a day on this thing and it really takes a long time to get to work at 30mph.
Any ideas?
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Post by katastroff on Jul 15, 2012 7:18:24 GMT -5
You're getting ram effect. Either rejet or try to restrict you air intake somehow.
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Post by larry001964 on Jul 15, 2012 7:18:37 GMT -5
Did you pull off the airbox ?
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Post by psychedelicode on Jul 15, 2012 7:28:46 GMT -5
Nope, airbox is still there. have done no mods to the motor at all. It's plenty fast for me, I just wish it was not so short (it hurts my back to ride). And, did a bit better on the hills. I'm only climbing hills at 20-25 unless I hit the bottom at 50, even then I'm sometimes only doing 30 by the top. I think iIneed new variator rollers. I'm going to tape one of the holes up and see if that helps.
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Post by larry001964 on Jul 15, 2012 7:39:50 GMT -5
Then i would agree with katastroff on the ram air effect..
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Post by psychedelicode on Jul 15, 2012 7:50:08 GMT -5
Hmmm, Ram air scoot. Didn't Pontiac claim a 15hp boost on the Firebird with ram air? Maybe I should try to utilize this. I just put a big ol' bolt in one of the intake holes. Helped out a ton. Doing 45 now again. I expected a drop in top speed with the removal of the plastics. I can suck up 2mph. I also notice that if i wear jeans it makes the problem worse. I think its because of my pant leg changing airflow to the intake. I am going to try to re route the intake to the front of the scoot. I don't like the idea of having to re jet. but will if I have to. Re jetting seems like it can be a hassle, alot of trial and error. I don't know much about these little motors. They seem very finiky about backpressure and Intake restriction. I have worked on many auto carbs, they are not very picky unless you dealing with a dang quadrajet.
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Post by larry001964 on Jul 15, 2012 8:03:42 GMT -5
Your other option is to put on a uni filter and maybe up jet a bit for it.. With the uni filter being at the back of the carb that should get rid of the ram air effect..
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Post by skuttadawg on Jul 15, 2012 8:13:02 GMT -5
You would need an unrestricted exhaust for it to work and upjet the carb
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Post by katastroff on Jul 15, 2012 8:29:52 GMT -5
Yup. what goes in, most come out.
Airbox/ Uni filter will only work good if you follow the path to the end.
Uni filter->up jetted carb -> unrestricted exhaust
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Post by psychedelicode on Jul 15, 2012 8:33:07 GMT -5
Wouldn't the uni get soaked/really dang dirty if it were located behind the carb? I have a rear fender but it does not extend all the way to the motor. I'm always hosing the case down after it rains because of all the crap that builds up. As a temp fix for the ramminng issues. I pulled the restrictor off the CVT intake and put it on the engine intake. The holes in it are smaller and that is better than a bolt that is going to fall out one of these days. I plan on chopping half of the CVT case off anyway, The belt has a tendency to smell like its melting after holding 40+ mph for a half hour at a time before I pull over for a cool down and soda halfway to work. My last scoot was a piaggio bv200 that i used to run around san francisco on. It only made it to 3200mi before it gave up the ghost. I am actually impressed that this chinese one did not blow up in the first 1500. I always thought the piaggios were nice scoots...i guess they are just overpriced ones. Of course that one did 75 coming across the bay bridge and handled like my suzuki SV650 and I had no fear of doing stoppies. I don't trust the frame on the jonway for that kind of abuse. I kinda don't trust it for 45mph and dodging potholes because i'm paranoid the fork is going to collapse. My warped front disc don't add no confidence either.
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Post by larry001964 on Jul 15, 2012 8:42:05 GMT -5
Well you don't have to do much talking to me to convince me about not using a uni filter.. Not a big fan of them anyway, and im getting ready myself to go back to the airbox design.. Another option perhaps better might be to just add to the snorkel intake with a tube so it's bent backwards and secure it down on top of the airbox.. Just an idea
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Post by psychedelicode on Jul 15, 2012 8:58:32 GMT -5
That's a GREAT idea. I just put a snorkel on it from a old shop vac hose. but I had run it to the front of the scoot with the smaller restrictor. It didn't really want to run. I'm going to try your way.
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Post by psychedelicode on Jul 15, 2012 9:04:26 GMT -5
I could also run it into the underseat compartment? Or would that be too hot and stale?
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Post by larry001964 on Jul 15, 2012 9:11:02 GMT -5
I could also run it into the underseat compartment? Or would that be too hot and stale? Ill be honest I'm not sure, where ever you put it, you will want it so it don't catch a lot of water. I would think the cleaner fresher air would work better.. And so the forward pressure of the bike don't create the ram air effect into the tube..
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Post by sirtokesalot on Jul 15, 2012 9:13:57 GMT -5
what ive noticed with these engines is the shorter the intake the better it seems to run.
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Post by psychedelicode on Jul 15, 2012 9:32:28 GMT -5
Just did larrys reverse snorkel...Seems to have worked but I will not know for sure until tomarrow when I go to work. I may have lost a touch of top end. Not sure its from wind resistance or because of the new snorkel. I am going to try to adjust the carb and see if it makes any difference. Gonna be fun stopping every 10 minutes on my way to work to take a screwdriver to the carb. At least there is no bodywork in the way....
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Post by larry001964 on Jul 15, 2012 9:45:38 GMT -5
Just did larrys reverse snorkel...Seems to have worked but I will not know for sure until tomarrow when I go to work. I may have lost a touch of top end. Not sure its from wind resistance or because of the new snorkel. I am going to try to adjust the carb and see if it makes any difference. Gonna be fun stopping every 10 minutes on my way to work to take a screwdriver to the carb. At least there is no bodywork in the way.... I'm glad it's working better for you, I know that those that deal with heating and air conditioning, will tell you the bend it self will cause a small amount of restriction in airflow.. You may need to compensate for this a little, just not sure how..
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Post by psychedelicode on Jul 15, 2012 9:54:17 GMT -5
Yeah and the corrugated tubing is causing massive turbulence too most likely.
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Post by skuttadawg on Jul 15, 2012 9:58:17 GMT -5
Make a lid for the airbox with a flared opening
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Post by larry001964 on Jul 15, 2012 9:59:57 GMT -5
Yeah and the corrugated tubing is causing massive turbulence too most likely. I have another idea, How about drilling one 3/8" hole in the underside of the tubing just before it bends up and around just after where it connects to the airbox, so that it can draw the extra air needed free of the restriction created by the bend and corrugations ?
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Post by psychedelicode on Jul 15, 2012 10:06:10 GMT -5
Skutta, What do you mean by a "flared opening" Larry, i am not in any short supply of corrugated tubing. I will give your idea a shot.
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Post by skuttadawg on Jul 15, 2012 10:18:11 GMT -5
Like a snorkel hood scoop on a car . Maybe modding the lid would be much easier than create a new one
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Post by psychedelicode on Jul 15, 2012 10:22:39 GMT -5
I also thought about plugging the restrictor holes and drilling new ones in the rear of the airbox. That kinda goes with your idea scutta.
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Post by larry001964 on Jul 15, 2012 10:49:44 GMT -5
I also thought about plugging the restrictor holes and drilling new ones in the rear of the airbox. That kinda goes with your idea scutta. I did that to my old airbox, drilled the holes at the back in the bottom of the lid.. so that way the air still passed thru the filter... worked very well....
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Post by headonz on Jul 15, 2012 20:00:58 GMT -5
Hi, all!........... i commute 100-130miles a day on this thing and it really takes a long time to get to work at 30mph. I'm seriously impressed ,you must have endless patients and an iron butt ;D
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Post by psychedelicode on Jul 16, 2012 14:34:15 GMT -5
Yeah, I cant say it don't hurt. That's why I'm starting the naked stretch. I have ridden things with two wheels for most of my soon to be 30 years, (not that that's alot) But you learn to live to ride. If I could ride my CX500, SV650, or KLR650 without paying up the ying for the ride, I would though. They are all more comfortable than my scoot but there is something about tiny tires and 50cc that I really enjoy, Maybe it's MPG, maybe its the funny looks I get when I pass people, maybe anything too much more powerful I get too comfy with. idk. But I like it!
I have the harness in pieces right now to rewire it for cleaner looks, its not in the photos they were taken early this morning and I have been workin' on it most of the day. I moved the snorkel to behind the front seat. It seems to work ok, better than doubled up on top of the airbox anyway, I still cant get the same power as before the bodywork removal though. Top end is a bit reduced and right about 30 when the CVT stops shifting and it's all motor there is a skip in power for about 2mph, then she starts getting into the powerband, although it's just not the same as before. I think I'm going to leave the motor alone for now, other than a re jet and exhaust mod (If anyone knows how to do this to a stock exhaust it would be great if you could pipe in:) pun intended.
Reallistically though my main goal is to rebuild the trans next with better components (is there such a thing? They are all from china regardless), to improve the hill power and acceleration (my trans is starting to make funny noises). After that I might consider a bbk exhaust and new carb. Probably after the stretch though.
At 2661.2 miles though I might just get a new motor and do the work on it. Then, put it on post stretch. BTW, some pictures so you all know I'm not bullshifting:
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Post by psychedelicode on Jul 16, 2012 15:58:35 GMT -5
totally not letting me post photos, Do i have to link a photobucket or something?
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Post by headonz on Jul 16, 2012 18:06:41 GMT -5
Yes. I also have my harness like a birds nest for the same out come hopefully !! My first venture into wiring of any sought so taking a little time to work it through.Going to run all back lights harness up the frame and have moved the ignition,rectifier,ballast resister and flasher unit ect to under the floor boards so now only have a 5 wire loom going up to the front lights/controls.I have the same issues with the air filter you have.Not found a solution yet.
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Post by larryw on Jul 17, 2012 20:00:05 GMT -5
When you remove the bodywork is it like a ruckus? Could you look into a ruckus airbox? Just throwing it out there I have no idea. lol
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Post by psychedelicode on Jul 20, 2012 18:04:00 GMT -5
No, it is not like a ruckus. I still have not finished my harness. And put all the restrictors back on the airbox and returned it to stock. Then I moved the clip on the needle up just a notch and richened the air screw. Did my third valve adjustment They were getting LOUD!. Runs like I never touched it unless a semi passes me and i get wind buffeted, then it almost dies and I go from 45 to 20 in about 3 seconds flat. I have some 5g sliders on the way and a 85-95 jet kit. once I have them I will try de-restriction again. Running over 2900 miles now. In just a month. I am very suprised at the reliability of these scoots. I ride WFO for 30 miles take a soda break for cool down and then do it again all the way to work in the morning, rinse and repeat going home. I am almost to the same mileage as my piaggio before it grenaded and this one cost about $3000 less, and I have not had to fix anything at all on it. Just oil, gear oil and, valve lash. I dont have any delusions that this engine is going to last forever but I am very suprised at how well it has done so far. I am debating getting a spare engine. I dont know when it will blow (mechanics stethescope sounds beautiful) But i dont think i have ever seen one with more than 5000 on it. seeing as that is sometime next month I think I need to start the search. Who makes the better QMB motors. I was thinking a lifan, but can't find any retailers, and am not sure about just buying a china one off of ebay. Who makes or sells the better taiwan motors?
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